Bootstrap is the most popular HTML, CSS, and JavaScript framework for building responsive, mobile-first projects on the web. Tailwind CSS, on the other hand, is the most popular utility-first CSS framework for fast UI development.

The main difference between TailwindCSS and Bootstrap is that Tailwind CSS is not a UI kit. Unlike UI kits such as Bootstrap, Bulma, and Foundation, Tailwind CSS doesn’t have a default theme or built-in UI components. Instead, it comes with predesigned widgets you can use to build your site from scratch.

Bootstrap is known for its responsiveness, whereas proponents of Tailwind CSS typically value the framework’s customizability. The best choice for you depends on your priorities and project requirements, but let’s talk about why Tailwind CSS is quickly gaining popularity and more widespread use.

The "CSS Box Model" is a container that contains multiple properties including borders, margin, padding, and the content itself. It is used to create the design and layout of web pages. It can be used as a toolkit for customizing the layout of different elements. The web browser renders every element as a rectangular box according to the CSS box model. Box-Model has multiple properties in CSS. Some of them are given below:

Content:This property is used to displays the text, images, etc, that can be sized using the width & height property.

Padding: This property is used to create space around the element, inside any defined border.

Border: This property is used to cover the content & any padding, & also allows to set the style, color, and width of the border.

Margin: This property is used to create space around the element ie., around the border area.

By adding semantic tags to your document, you provide additional information about that document, which aids in communication. Specifically, semantic tags make it clear to the browser what the meaning of a page and its content is.